A headblock and fingerboard support assembly for a stringed instrument includes a fingerboard support assembly for mounting to a neck and fingerboard of the stringed instrument. The fingerboard support assembly further includes a plate having an integrated rail structure. A headblock has an integrated channel for receiving the integrated rail structure. The headblock is adapted to secure to the fingerboard support assembly. A method of assembling a stringed instrument includes mounting a plate structure to a neck and fingerboard of the stringed instrument, where the plate includes an integrated rail, and mounting a headblock to an interior surface of a body of the stringed instrument, where the headblock has an integrated channel structure for receiving the integrated rail of the plate structure.